Cloning of the PacB-Ter Region from Plasmid Mip233 (IncHI3) and Their Expression in E. coli Ton, Tol Mutants

On the mechanism of resistance to channel-forming colicins (PacB) and tellurite, encoded by plasmid Mip233 (IncHI3)

“…Results shown in Table 2 indicate that pre‐growth of transformants in presence of cysteine or sulfur increases the cell's ability for further growth at high tellurite concentrations (up to 500 μg ml −1 ). However, and in contrast to expectations [10,15], pre‐growth of transformants in the presence of sub‐lethal concentrations of tellurite did not increase cell growth over the level expressed by culture control. Analogous results were obtained when cells were pre‐grown in the presence of colicins.…”

“…Studies on expression of both properties have been done using E. coli strains with alterations in Ton and Tol translocation systems. Our results indicated that for the expression of both phenotypes, the intact product of gene tolC is required since TolC mutants carrying pB22 are unable to acquire the phenotype PacB‐Te r [15].…”

“…However, Hill et al [14] showed that this property in pMER610 is constitutive and not affected by prior exposure to sub‐toxic levels of tellurite. Recently, we cloned a region of plasmid Mip233 (IncHI3), pB22 clone, able to confer both properties (PacB + ‐Te r ) [15]. pB22 (2200 bp) represents the smallest DNA segment so far isolated that is able to fully express tellurite resistance (K 2 TeO 3 minimal inhibitory concentration=1024 μg ml −1 ) and resistance to channel‐forming colicins [15].…”

NMR Structure and Calcium-Binding Properties of the Tellurite Resistance Protein TerD from Klebsiella pneumoniae

“…8 Moreover, colicin resistance and tellurite resistance plasmids are genetically and physically linked to cope with stress environments. 9 Indeed, transpositions into TerC, TerD, and TerZ were found to reduce or abolish all phenotypes of phage inhibition, tellurite resistance, and colicin resistance. 10 These findings indicate that Ter genes mediate diverse cellular responses.…”

On the mechanism of resistance to channel-forming colicins (PacB) and tellurite, encoded by plasmid Mip233 (IncHI3)

“…A region of the plasmid Mip233 (incompatibility subgroup HI3) encoding the phenotypes for resistance to channel-forming colicins (character PacB) and potassium tellurite (Te r ) was recently cloned in our laboratory [15]. So far, clone pB22 is the smallest (2200 bp) functional DNA segment isolated that is able to confer both phenotypes.…”